We have seen hung devices and failures during SPI transactions on
Fritzbox devices with a gluon based freifunk network. We have narrowed
down that disabling DMA for spi fixes the problem, so disable dma for
the SPI controller on the Fritzbox 4040.
Signed-off-by: Rouven Czerwinski <rouven@czerwinskis.de>
Link: https://github.com/openwrt/openwrt/pull/15966
Signed-off-by: John Crispin <john@phrozen.org>
d67963943b